This invention relates to acetylenic polyorganosiloxane compounds. More particularly, it relates to a class of diacetylenic polyorganosiloxanes and their curing.
Polyorganosiloxanes (hereinafter sometimes designated "silicones") having acetylenic moieties are known in the art, being disclosed in a number of publications. For example, compounds having conjugated diacetylenic groups bound directly to silicon atoms are disclosed in Son et al., Macromolecules, 28, 399-400 (1995), and in Parnell et al., J. Poly. Sci., Poly. Chem. Ed., 11, 1107-1110 (1973). Genera of compounds in which similar diacetylenic groups are present in combination with amide or ester groups and silicone moieties are among the subjects of European patent application 210,056 and Lai et al., Mol. Cryst. Liq. Cryst., 188, 25-39 (1990). Silicones having pendant phenyldiethynylphenyloxyalkyl groups are disclosed in Hsu et al., Poly. Prep., 33, 214-215 (1992). Diacetylenic silicones containing a Si--O--C linkage are disclosed in German published applications 4,302,993 and 4,303,080.
Such materials have potential for being cured, as by heat or radiation, to produce materials useful, for example, as release coatings or conformal coatings. However, they suffer from various disadvantages including high cost of preparation and chemical instability, the latter being particularly true of compounds having a Si--O--C linkage.
French patent applications 96/11,999 and 96/12,000 disclose polymeric compositions containing ether groups in combination with diacetylenic moieties. However, no silicone moieties are present.
It remains of interest, therefore, to develop diacetylenic silicone compounds which are relatively inexpensive, stable and easily cured.